The candidate, Holly Thompson M.D., is committed to pursuing a career in patient-oriented clinical research. She currently is completing a 5 year Clinical Investigator Track in Internal Medicine and Endocrinology at the University of Colorado Health Sciences Center (UCHSC) in Denver. The candidate's long-term career goal is to become an independent clinical investigator in the area of obesity and body weight regulation. Her specific area of interest is in the reduced-obese state and in understanding mechanisms driving weight regain following a weight loss. The Candidate and her Mentor, Dr. James Hill, have mapped a career plan for the candidate to develop the skills and expertise necessary to become an independent clinical investigator. This plan takes advantage of the many opportunities for collaborations and the high level of obesity expertise that exists within this institution. Her mentor, Dr. James Hill, has been successfully funded for obesity research since 1982 and is an international leader in obesity research. He is totally committed to helping the candidate achieve her career objectives. The candidate's proposed research plan takes advantage of a unique registry of subjects who have been successful at long term weight loss and maintenance. She proposes to compare some of these subjects (who have maintained a 30 pound weight loss for a minimum of 5 years) to individuals who have lost a similar amount of weight but have only maintained the reduction for 3 months. The short-term weight reduced subjects are assumed to be a "susceptible" group, and we anticipate that most will regain their lost weight within 1 year. In contrast, we assume that subjects who have maintained a weight loss for 5 years are not susceptible to weight regain. By comparing the two groups, the candidate hopes to identify metabolic factors that may explain susceptibility to weight regain. The proposed project will provide the applicant important experience in conducting weight-loss interventions, in the use of sophisticated tools to assess energy metabolism, and further experience in working with successful weight-reduced subjects. These are important skills and experiences for the candidate's career plan.